The present invention generally relates to improvements in safety needled medical devices which are designed to minimize the incidence of accidental pricking of the skin and resulting spread of infectious diseases by an exposed contaminated needle after use thereof. The disclosed devices may be used as blood collection tube holders, syringes with or without an attached needle, and prefilled syringes.
Accidental needlesticks have long been a problem in the medical profession. Accidental needlesticks most often occur during the recapping of a contaminated needle or immediately after use and prior to safe disposal. Such needlesticks place the medical professional (clinician) at risk. When needles are not recapped, additional accidental needlesticks are caused by uncapped needles found in patient beds, linens, and in garbage cans, and place health care house keeping and sanitation personnel at risk. Because accidental needlesticks can now result in deadly incurable diseases as well as the previously appreciated serious, but curable diseases, the need for eliminating the needlestick problem has reached extreme urgency. In addressing the urgency, many devices have been proposed. Indeed, the prior art discloses a number of devices which are arranged to shield the needle of the device after use, but none are as simple to manufacture, assemble, and use as the devices of the present invention. A benefit of the devices of the present invention is that the devices require no change in the method of use or technique by medical personnel, i.e. the medical practioners will use the devices in the same way they previously used standard hypodermic syringes, IV catheters, and blood collection tube holders, except that after use they will move a shield to cover the exposed contaminated needle in a very easy, simple and straightforward manner.
Included in the prior art among many safety devices are safety-needled syringes such as are disclosed in U.S. Pat. Nos. 2,571,653 to Bastien, 4,026,287 to Haller, 4,425,120 to Sampson et al., 4,573,976 to Sampson et al., 4,631,057 to Mitchell, et al. 4,643,199 to Jennings, Jr. et al., 4,655,751 to Harbaugh, 4,666,435 to Braginetz, 4,681,567 to Masters et al. None of these devices, however, have gained acceptance due to the fact that they require many complex pieces and thus become expensive to manufacture and assemble, and/or because in utilizing the devices, they require the clinician's procedure and technique to change. For example, in U.S. Pat. No. 4,425,120 to Sampson et al., a complex arrangement of tracks including axial and circumferential components of shield and syringe members are required, making manufacture and assembly more difficult and expensive. Also, in use, the clinician must rotate the shield relative to the syringe tube and force the track engaging member of the syringe through a restriction in the circumferential portion of the track in the shield to lock the shield relative to the syringe tube. The U.S. Pat. No. 4,631,057 to Mitchell requires a collar member over which a shield slides. The device is complex, difficult to manufacture and assemble, and requires permanent attachment of the collar to the syringe tube. The U.S. Pat. No. 4,573,976 to Sampson et al., requires additional intricate members which are attached to both the tube and the shield and which provide a locking action. The additional members are expensive to manufacture and assemble, unwieldy to handle, and would require a clinician to develop a new technique for utilization.
U.S. Pat. No. 4,655,751 to Harbaugh requires at least one slide groove to maintain the shield in the proper rotational axis and to thereby align a pair of ears on the shield with either one of two pairs of pockets in the outer surface of the syringe tube. Besides being relatively expensive to manufacture and assemble due to the ears and pockets, it also requires flexing of the shield to move it to the needle-shielding position, and thus has the potential for cracking or breaking. Similarly, U.S. Pat. No. 4,681,567 to Masters et al., requires a slide grooves in a shield and knobs or ears on the tube. Restrictions in the groove provide locking positions for the shield. Again, however, the knobs may be costly to manufacture and assemble and are prone to breaking. Also, it is not evident how such a device could be manufactured without sonically welding the shield around the tube, as any attempt to slide the shield over the tube and into a non-extended position would require overcoming the same locking action which is used to finally lock the shield relative to the tube.
U.S. Pat. No. 4,666,435 to Braginetz requires a complex and difficult to manufacture arrangement of tracks, rails, detents and stop surfaces, and would be much more expensive to make and assemble than the present invention. Further, to lock the syringe tube and shield, the user must step through a predetermined sequence of relative rotational and longitudinal movements between the shield and the syringe tube. U.S. Pat. No. 2,571,653 to Bastien is simpler in design and has a single latch secured by a tensioning device to lock the shield at fixed points on the syringe tube, but the shield would not be as secure in its position covering the needle due to the single latch, and any mishandling of the device could cause movement of the tensioning device and exposure of the needle.
Finally, U.S. Pat. Nos. 4,026,287 to Haller and 4,643,199 to Jennings, Jr. show safety devices which utilize a technique of withdrawing the needle into the tube in order to render the needle harmless. These devices, and others like these typically require additional parts and are difficult to manipulate.